1) Technical Field
The present invention belongs to the field of dry separation and in particular relates to a dry method heavy medium separator adopting a dry method heavy medium separation bed and a dry method heavy medium separation device, especially applicable to separation of coal from other ores with different densities and belonging to solid separation equipment.
2) Background of the Art
At present, dry method heavy medium separators used in industrial production at home and abroad are mainly air jig and air table which replace water with air as a separation medium. With poor separation effect, low production capacity, and high wind power requirement, they have been eliminated gradually.
Since the 1960's, scholars such as Douglas E in America and Beeckmans J M in Canada had been doing researches on dry separation based on a general gas-solid fluidized bed successively and its separation principle is that with a fine particle material (such as magnetite powder) as a dense medium, a gas-solid two-phase fluidized bed with certain density is formed under the action of a uniform upflow, separation materials (such as coal) are layered according to the density of the fluidized bed after being fed into a bed. However, these scholars, by just basing on a material replacement principle of a fluidized bed in the chemical industry, did not deeply research concentrated phase high density fluidization characteristics (such as an air distributor and grain size distribution of a dense medium) suitable for coal separation, and thus the industrialization of their researches was not achieved.
China University of Mining and Technology has been engaged in the research on fluidized dry coal preparation since the 1980's and developed gas-solid tow-phase flow based dry separation technology and equipment. Fluidizing gas and a dense medium (such as magnetite powder) with a certain particle size form a concentrated phase fluidized bed; under the uplift action of global density of the fluidized bed in a gas-solid tow-phase flow bed, separation materials are layered according to the bed density; material with density lower than the bed floats up while material with density higher than the bed density goes down, therefore the effective separation of the separation materials can be realized. The gas-solid heavy medium fluidized bed provides a new efficient clean dry separation way for coal in the world, with a wide application prospect and a significant application value. Based on its studies on the theory and process of dry method heavy medium separation since 2006, after analyzing a great deal of research data of dry method heavy medium separation, Tangshan Shenzhou Machinery Co., Ltd. has successfully researched and developed a new generation of dry method heavy medium device and put it into industrialization successfully.
However, the past studies on a dry-method heavy medium separator have the following problems: it is difficult to improve the separation accuracy and efficiency of difficult separation coal since fluidization density is instable and air flow distribution is not uniform in a fluidization process; moreover, due to such problems as the medium separating efficiency of an existing medium separating screen for fine materials is low and the magnetic medium content of the fine materials subjected to medium separation is high, the medium separating efficiency for fine materials cannot be improved.